Ported horizontal_projection() to XS

lib/Slic3r/TriangleMesh.pm

@@ -29,24 +29,4 @@ sub bounding_box {
     return Slic3r::Geometry::BoundingBox->new_from_bb($self->bb3);
 }
 
-# this will return *scaled* expolygons, so it is expected to be run
-# on unscaled meshes
-sub horizontal_projection {
-    my $self = shift;
-    
-    my ($facets, $vertices) = ($self->facets, $self->vertices);
-    
-    my @f = ();
-    foreach my $facet (@$facets) {
-        push @f, Slic3r::Polygon->new(
-            map [ map $_ / &Slic3r::SCALING_FACTOR, @{$vertices->[$_]}[X,Y] ], @$facet
-        );
-    }
-    
-    $_->make_counter_clockwise for @f;  # do this after scaling, as winding order might change while doing that
-    
-    # the offset factor was tuned using groovemount.stl
-    return union_ex(offset(\@f, Slic3r::Geometry::scale 0.01), 1);
-}
-
 1;

xs/src/TriangleMesh.cpp

@@ -1,4 +1,5 @@
 #include "TriangleMesh.hpp"
+#include "ClipperUtils.hpp"
 #include <queue>
 #include <deque>
 #include <set>
@@ -575,6 +576,28 @@ TriangleMesh::merge(const TriangleMesh* mesh)
     stl_get_size(&this->stl);
 }
 
+/* this will return scaled ExPolygons */
+void
+TriangleMesh::horizontal_projection(ExPolygons &retval) const
+{
+    Polygons pp;
+    pp.reserve(this->stl.stats.number_of_facets);
+    for (int i = 0; i < this->stl.stats.number_of_facets; i++) {
+        stl_facet* facet = &this->stl.facet_start[i];
+        Polygon p;
+        p.points.resize(3);
+        p.points[0] = Point(facet->vertex[0].x / SCALING_FACTOR, facet->vertex[0].y / SCALING_FACTOR);
+        p.points[1] = Point(facet->vertex[1].x / SCALING_FACTOR, facet->vertex[1].y / SCALING_FACTOR);
+        p.points[2] = Point(facet->vertex[2].x / SCALING_FACTOR, facet->vertex[2].y / SCALING_FACTOR);
+        p.make_counter_clockwise();  // do this after scaling, as winding order might change while doing that
+        pp.push_back(p);
+    }
+    
+    // the offset factor was tuned using groovemount.stl
+    offset(pp, pp, 0.01 / SCALING_FACTOR);
+    union_(pp, retval, true);
+}
+
 #ifdef SLIC3RXS
 SV*
 TriangleMesh::to_SV() {

xs/src/TriangleMesh.hpp

@@ -6,6 +6,7 @@
 #include <vector>
 #include "Point.hpp"
 #include "Polygon.hpp"
+#include "ExPolygon.hpp"
 
 namespace Slic3r {
 
@@ -31,6 +32,7 @@ class TriangleMesh
     void slice(const std::vector<double> &z, std::vector<Polygons> &layers);
     TriangleMeshPtrs split() const;
     void merge(const TriangleMesh* mesh);
+    void horizontal_projection(ExPolygons &retval) const;
     stl_file stl;
     bool repaired;
     

xs/xsp/TriangleMesh.xsp

@@ -24,6 +24,8 @@
     void rotate(double angle, Point* center);
     TriangleMeshPtrs split();
     void merge(TriangleMesh* mesh);
+    ExPolygons horizontal_projection()
+        %code{% THIS->horizontal_projection(RETVAL); %};
 %{
 
 SV*